Optimal Reaction Pathway Research Articles

Research on reaction mechanisms on chemical looping gasification of naphthalene over NiFe2O4 for syngas production: An experimental and theoretical study

The effective removal of tar during biomass gasification is a significant challenge that can be addressed by chemical looping gasification (CLG), which offers a promising alternative for converting biomass into syngas with reduced tar generation. In this study, we investigated the mechanism of CLG of naphthalene as a model biomass tar compound over NiFe2O4 to produce syngas. Both experimental and simulation results indicate the optimal operating conditions for syngas production are 1000℃ and an O/C ratio of 1:1. Under the optimal reaction conditions, the experimental and simulated CO yields were 67 vol% and 73 vol%, respectively, while H2 yields were 22 vol% and 24 vol%. Additionally, carbon conversion rates reached 78% and 76%. Thermodynamic calculations and molecular dynamics simulations revealed that the reactions proceed spontaneously, with increasing temperature favoring naphthalene conversion and syngas production. Density functional theory results indicate that the reaction pathway centered on the carbon at the α-position is the key to naphthalene and NiFe2O4 conversion. The optimal reaction pathways for H2 and CO formation were explored. This study on the CLG of naphthalene over NiFe2O4 provides a theoretical basis for the development of more efficient CLG processes with reduced tar formation.

DFT Investigation on Palladium-Catalyzed [2 + 2 + 1] Spiroannulation between Aryl Halides and Alkynes: Mechanism, Base Additive Role, and Solvent and Ligand Effects.

Transition metal-catalyzed spiroannulations are practical strategies for constructing spirocyclic skeletons of pharmaceutical and biological significance, yet the microscopic mechanism still lacks in-depth explorations. Here, the palladium-catalyzed [2 + 2 + 1] spiroannulation between aryl halides and alkynes was studied by employing the density functional theory (DFT) method. Based on comprehensive explorations on a couple of possible reaction pathways, it is found that the reaction probably experiences C-I oxidative addition, alkyne migration insertion, Cs2CO3-assisted aryl C-H activation, C-Br bond oxidative addition, C-C coupling, arene dearomatization and reductive elimination in sequence and leads to the formation of the spiro[4,5]decane pentacyclic product (P) ultimately. Among these, the C-Br bond oxidative addition step acts as the rate-determining step (RDS) of the whole reaction, featuring a practical free energy barrier of 32.4 kcal·mol-1 at 130 °C. Computationally predicted kinetics such as half-life transferred from the RDS step's barrier on the optimal reaction pathway (1.2 × 101 h) coincides well with corresponding experimental results (91% yield of the spiro[4,5]decane pentacyclic product P after reacting 10 h at 130 °C). In addition, theoretical predictions regarding the solvent/ligand effects and base additive role in the reaction, rationalized by distortion-interaction/natural population/noncovalent interaction analyses, are also in good agreement with experimental data and trend. This good agreement between experiment and theory makes sense for new designations and further experimental improvements of such Pd-catalyzed transformations.

Advanced approach for active and durable proton exchange membrane fuel cells: Coupling synergistic effects of MNC nanocomposites

AbstractAtomically dispersed metal and nitrogen co‐doped carbon (MNC) is a promising oxygen reduction reaction (ORR) catalyst for electrochemical energy storage and conversion applications but typically suffers from low durability and activity under the acidic conditions of practical polymer electrolyte exchange membrane fuel cells (PEMFCs). Recently, the performance of MNC nanocomposites under acidic ORR conditions has been enhanced by exploiting the synergistic coupling effects of their constituents (single‐atom sites, nanoclusters, and nanoparticles). The unique geometric structures formed by the coupling of diverse sites in these nanocomposites provide optimal electronic structures and efficient reaction pathways, thus resulting in high activity and long‐term durability. This work provides an overview of MNC nanocomposites as ORR electrocatalysts under practical PEMFC conditions, focusing on activity and durability enhancement methods and highlighting the strategies used to prepare electrocatalytically efficient MNC nanocomposites containing no or low amounts of platinum group metals. Progress in the development of advanced MNC nanocomposites as acidic ORR catalysts is discussed, and the pivotal role of synergistic effects resulting from the coupling sites within the nanocomposites is explored together with the characterization methods used to elucidate these effects. Finally, the challenges and prospects of developing MNC nanocomposites as next‐generation electrocatalysts are presented.image

Computational Characterization of the On-Surface Synthesis of Low-Dimensional Nanostructures

On-surface chemistry represents a fast-growing field allowing to synthesize molecular structures not available by traditional wet chemistry. In this context, high-resolution scanning probe microscopy techniques are able to provide unprecedented spatial resolution, allowing to precisely identify individual products of the reactions. Nevertheless, a deep understanding of the reaction mechanism under the conditions imposed by the substrate remains unknown.Nowadays, various computational strategies are employed to characterize the optimal reaction pathways of the chemical processes that take place on the surfaces of solids. For example, one of the most popular approaches is the nudged elastic band (NEB) as well as different transition state theory methods beyond it. These approaches had demonstrated their capability to characterize the potential energy landscape of the reaction pathways [1-2]. Another approach that had attracted the interest of the on-surface synthesis community is the application of molecular dynamics (MD) methods, within the canonical ensemble, and based on the QM/MM (quantum mechanics/molecular mechanics) of the interatomic forces [3-4]. This approach, which combines Density functional theory (DFT) and empirical force fields to describe the interaction forces, allows to simulate very large systems, at a very low computational cost while still accounting for the crucial quantum mechanics interactions. Also, such temperature-dependent simulations include the effect of entropy, vibrations modes, concerted motion, etc.I will present the experimental and computational results of different projects in which we have made use of the aforementioned computational approaches to achieve a better understanding of the on-surface synthesis experiments performed by the group. For example, the rationalization of the selective cyclodehydrogenation of non-benzenoid nanographenes deposited on a Au(111) substrate by means of temperature-dependent MD calculations and the analysis of the obtained vibrational modes (See Figure 1a). The group had also studied the stepwise transformation of coronene-based organometallic networks into two-dimensional covalent patches through intermolecular homocoupling (See Figure 1b). We had as well investigated the transformation of indenyl precursors, through a triple C-H cleavage followed by a peripheral directed homocoupling, to form a polyacetylene backboned polymer that features a parity dependent and highly delocalized soliton in-gap state (See Figure 1c).

High C‐Selectivity for Urea Synthesis Through O‐Philic Adsorption to Form *OCO Intermediate on Ti‐MOF Based Electrocatalysts

AbstractThe advent of utilizing nitrate (NO3−) for electrochemical co‐reduction with carbon dioxide (CO2) to effectively synthesize high‐value‐added organic nitrogen compounds has captured the attention of the environmental and energy fields. C─N coupling is a key step during the electrochemical co‐reduction process. An effective strategy to improve the efficiency of synthesis is to explore the optimal reaction pathway and coupling active species. Herein, a p‐type semiconductor nanosphere (Ti‐DHTP) is presented for electrochemical co‐reduction to synthesize urea by combining CO2 and NO3−. At a low voltage of −0.6 V versus RHE, the electrochemical synthesis of urea exhibits 95.5% C‐selectivity and 21.75% Faraday efficiency. Comparative experiments, in situ experiments, and theoretical simulations confirm that a new coupling pathway for the synthesis of urea from *NH2 and *OCO intermediates become a key step in Ti‐DHTP‐driven C─N coupling. Moreover, the more efficient *OCO intermediate inhibits the generation of large amounts of C‐bearing by‐products. Meanwhile, Ti‐DHTP has difficulty hydrogenating to form *COOH during the reduction of CO2 leading to the subsequent inability to produce *CO intermediates. This work reveals a new C─N coupling mechanism, which provides a feasible strategy for future research on the electrochemical synthesis of organic nitrogen‐bearing compounds.

Data-Driven Evolutionary Design of Multienzyme-like Nanozymes.

Multienzyme-like nanozymes are nanomaterials with multiple enzyme-like activities and are the focus of nanozyme research owing to their ability to facilitate cascaded reactions, leverage synergistic effects, and exhibit environmentally responsive selectivity. However, multienzyme-like nanozymes exhibit varying enzyme-like activities under different conditions, making them difficult to precisely regulate according to the design requirements. Moreover, individual enzyme-like activity in a multienzyme-like activity may accelerate, compete, or antagonize each other, rendering the overall activity a complex interplay of these factors rather than a simple sum of single enzyme-like activity. A theoretically guided strategy is highly desired to accelerate the design of multienzyme-like nanozymes. Herein, nanozyme information was collected from 4159 publications to build a nanozyme database covering element type, element ratio, chemical valence, shape, pH, etc. Based on the clustering correlation coefficients of the nanozyme information, the material features in distinct nanozyme classifications were reorganized to generate compositional factors for multienzyme-like nanozymes. Moreover, advanced methods were developed, including the quantum mechanics/molecular mechanics method for analyzing the surface adsorption and binding energies of substrates, transition states, and products in the reaction pathways, along with machine learning algorithms to identify the optimal reaction pathway, to aid the evolutionary design of multienzyme-like nanozymes. This approach culminated in creating CuMnCo7O12, a highly active multienzyme-like nanozyme. This process is named the genetic-like evolutionary design of nanozymes because it resembles biological genetic evolution in nature and offers a feasible protocol and theoretical foundation for constructing multienzyme-like nanozymes.

Insights into the Mechanism, Regio-/Diastereoselectivities and Ligand Role of Nickel-Initiated [3+2] Cycloadditions between Vinylcyclopropane and N-Tosylbenzaldimine

Density functional theory (DFT) was employed to explore the reaction mechanism, regio- and diastereoselectivities of nickel-initiated [3+2] cycloaddition between vinylcyclopropane (VCP) and N-tosylbenzaldimine assisted by phosphine ligands. Four different binding modes of the nickel center to VCP substrate were explored during the ring-opening of VCP, among which the C,C_anti and C,C_syn modes were verified to be the most accessible ones. Further explorations about four different phosphine ligand-assisted reactions based on the two most probable binding modes show that the difference in binding mode of bi- and monodentate phosphine ligands can vary the optimal reaction pathway, especially in the [3+2] cycloaddition process between the ring-opened intermediate and N-tosylbenzaldimine. The formation of C–C and C–N bonds between N-tosylbenzaldimine and the ring-opened intermediate through [3+2] cycloaddition is found to be stepwise, with the former acting as the rate-determining step (RDS) in most cases. Computed free energy barriers of RDS transition states on the optimal path I or II not only give out good predictions for reaction rates and half-lives, but also provide reasonable explanations for the major generation of cis-pyrrolidine. Noncovalent interaction analyses of key stationary points suggest the rate is influenced by both electronic effects and steric hindrance, while the diastereoselectivity is mainly controlled by electronic effects.

Mechanism and toxicity assessment of carbofuran degradation by persulfate-based advanced oxidation process.

The advanced oxidation process based on persulfate has been proven to be a promising method for degrading the highly toxic carbamate pesticide carbofuran (CBF). However, the mechanism of CBF degradation by sulfate radicals (SO4·-) and hydroxyl radicals (·OH) is still unclear and requires further research and discussion. This study investigated the mechanism and toxicity assessment of CBF degradation using density functional theory (DFT) theory calculation methods. The results indicated that SO4·- and ·OH can undergo addition and abstraction reactions with CBF. Thermodynamic and kinetic analysis showed that the abstraction reaction between SO4·- and the secondary H atom is the optimal reaction pathway, exhibiting the highest branching ratio (Γ = 41.84%). The rate constants for the reactions of CBF with SO4·- and ·OH at room temperature were found to be 3.66 × 109 and 8.96 × 108 M-1 s-1, respectively, which are consistent with experimental data reported in previous studies. The acute and chronic toxicity of CBF and its degradation products to aquatic organisms was predicted through an ecological toxicity assessment model. The toxicity of the degradation products was lower than that of the parent CBF, confirming the viability of using persulfate-based advanced oxidation processes for water treatment.

Dual roles derived from lattice incorporation of Cl- in ultrathin LiCoO2-xClx for water elelctrolysis

LiCoO2 is a kind of promising electrocatalyst for oxygen evolution reaction (OER), while it is difficult to successfully achieve the nanosheets morphology of LiCoO2 with regulated electronic configuration and optimal reaction pathway. Here, we demonstrate that doping Cl ion into the lattice of LiCoO2-xClx ultrathin nanosheets by alkaline molten salt method can bring out dual roles, which not only adjust the covalency of Co-O bond to improve OER activity, but also promote the leaching of Li to activate lattice oxygen. The deep delithiation of LiCoO2-xClx to produce O22– intermediates is inclined to be lattice oxygen mediated mechanism (LOM). The more oxygen vacancies due to the accurate lattice doping of optimized Cl- regulate the coordination environment and electron distribution of Co sites. The electrochemical measurements show that the overpotential of LiCoO2-xClx at 10 mA cm−2 for OER is reduced by 130 mV compared to LiCoO2 by solid phase synthesized. Additionally, the lattice doping of Cl- can make the current density increase from 7.55 to 26.88 A g−1 at 2.0 V in Anion-exchange membrane water electrolyzer (AEMWE). The dual regulation strategy based on lattice doping of halogen ions provides a new viewpoint by adjusting coordination environment and optimizing reaction path for OER.

Optimal Pathways for Nitric Acid Synthesis Using P-Graph Attainable Region Technique (PART)

Developing a chemical reaction network is considered the first and most crucial step of process synthesis. Many methods have been employed for process synthesis, such as the attainable region (AR) theory. AR states that a region of all possible configurations can be defined with all the potential products and reactants. The second method is process network synthesis (PNS), a technique used to optimise a flowsheet based on the feasible materials and energy flow. P-graph is an algorithmic framework for PNS problems. P-graph attainable region technique (PART) is introduced here as an integration of both AR and P-graph to generate optimal reaction pathways for a given process. A descriptive AR plot is also developed to represent all the possible solution structures or reaction pathways. A case study of a conventional nitric acid synthesis process was used to demonstrate this technique.

Optimal reaction pathways of carbon dioxide hydrogenation using P-graph attainable region technique (PART)

The attainable region interpretation of the thermodynamic principles has indicated that carbon dioxide (CO2) can be either hydrogenated directly to form dimethyl ether (DME) or gasoline. The process that converts CO2 to DME is more thermodynamically favourable at lower temperature. A certain thermodynamic temperature range (25 to 300 °C) is suggested for the conversion of CO2 to DME via a methanol intermediate pathway without addition of work. Optimal synthesis routes derived from P-graph's mutual exclusion solver were compared with reactions reported in literature and showed great correlation. The reactions collectively possess Gibbs free energy of less than zero, and negative enthalpy of reaction. With P-graph attainable region technique, the case studies have demonstrated that the synthesis of DME and gasoline using CO2 hydrogenation via methanol intermediate and carbon monoxide intermediate from Fischer–Tropsch synthesis is feasible with no work and heat requirement. Both case studies have demonstrated visual advantage of P-graph and data-driven applications. The benefit of integrating the P-graph framework with machine learning model like decision tree classifier was also demonstrated in the second case study as it solves topological optimisation problems without scaling constraints.

Theoretical insight into dimethyl carbonate carboxymethylation of alcohols assisted by Lewis acid proton carrier catalyst FeCl3

To extend the understanding of role of Lewis acid catalysts in dimethyl carbonate (DMC) chemistry, density functional theory (DFT) calculation is conducted to demonstrate the mechanism of DMC mediated carboxymethylation of ethanol catalysed by FeCl3. In parallel with the investigation based on transition state theory (TST), the nature of bonding of all studied species and bonding evolution along the optimal reaction pathways is explored via the topological analysis of electron localization function (ELF) and atoms in molecules (AIM) theory. Results indicate that hydrogen bond among alcohols promotes the molecules to form cyclic transition state, which facilitates reaction in the absence of catalyst. Additionally, FeCl3, acts as a Lewis acid proton carrier catalyst, is proved to reduce the reaction activation energy significantly. Finally, the calculated turnover frequency (TOF) of FeCl3 pathway relative to catalyst-free is 4.06 × 105, providing evidence that FeCl3 is an efficient catalyst for DMC chemistry.

Investigation of the Model-Dependent Reactivity of the Char-Bound Nitrogen Surface: A DFT Study.

The concern of energy and the environment provides great inducement for fundamental research on the mechanisms of oxidation of char-bound nitrogen (char(N)). In the present study, based on the armchair(N) model, we investigated its reaction mechanism at an atomistic level and with a comprehensive study of the effect of the model surface. Several pathways are found by density functional theory (DFT) calculations for the oxidation of armchair(N). The main gaseous species released during the oxidation are NO, HCN, CO, and CO2. The evaluated optimal reaction pathways are selected to investigate the model-dependent reactivity. According to our calculations, the oxidation of the simplified top armchair(N) model (TM) will be much more competitive than that of the simplified edge armchair(N) model (EM). In the route giving NO, the decreased stability of the intermediates makes the reaction of TM more favorable. In the route giving HCN, the described reduced mechanism and the larger exothermicity and lower highest-energy transition state will be responsible for the priority. Further analysis of the kinetics gives the evidence for the competitiveness: the rate constants for most of the steps of the TM, such as HCN desorption, surface bond dissociation, ring closure and opening, and oxygen insertion and migration, are higher than that of the EM. Therefore, a conclusion can be drawn that the oxidation of the armchair(N) will mainly take place from the top surface rather than the edge surface. The results can be used to supplement present understanding of the oxidation of armchair structure, which is extremely crucial for the development of the kinetics model to better predict the NOx emissions during the air-staged combustion.

An integrated framework for sustainable process design by hybrid and intensified equipment

With the increasing concern of the competitive market and carbon emissions, a sustainable, efficient process design becomes more and more important. The task of sustainable process design is to find efficient configurations and operating parameters to produce products or utilize materials. Currently, the scientific community's major focus is on separation synthesis, which aims to identify the best downstream separation configurations through different methods such as optimization, heuristic, and hybrid methods. Besides, innovative separation techniques with lower capital/operating costs and carbon emissions were proposed and identified to further improve the downstream process performance. However, most of the separations synthesis methods were based on conventional unit operations and usually applied for generating sustainable processes with a given reaction pathway without considering the possibilities of different raw materials. Generally, to produce a given target product, multiple reaction pathways are available, and each reaction pathway leads to different downstream processes. Also, applying intensification in the early stages of process design, e.g., separation synthesis, can generate sustainable process flowsheets with higher energy efficiency and lower environmental impact. This work aims to develop an integrated process synthesis framework, which includes reaction synthesis for the reaction pathways selection and separation synthesis involving intensified/hybrid units. So, for the new process design, given the product one needs to produce, this framework could identify the optimal reaction pathway with its best separation route. The developed framework was used to solve three case studies, including the new process design of dimethyl carbonate (DMC) production and retrofitting design of cumene and styrene production. For all the case studies, the framework was able to generate multiple innovative solutions that are sustainable and energy-efficient.

Theoretical study of the nitrosation reaction mechanism of N-nitrosation reaction catalyzed by the cupin domain of SznF enzyme toward the modified L-Arg with methyl nitrogen deprotonation

The SznF enzyme provides a novel approach to synthesize the N-nitrosourea pharmacophore. In this work, the modified L-Arg with methyl nitrogen deprotonation(L-DHMAd), a not yet studied substrate’s reaction mechanism of the critical N-nitrosation reaction catalyzed by the cupin domain of SznF enzyme is investigated, through the combined quantum mechanics/molecular mechanics method. Basis on our calculation results, the optimal N-nitrosation reaction pathway can be divided in to three reaction steps:1) superoxo addition with accompanying of Cε-Nω bond cleavage; 2) O1-O2 bond heterolytic cleavage; 3) NMe-Nω bond coupling. The first reaction step is the rate-determining step of the entire optimal reaction with an energy barrier of 20.6 Kcal/mol. Significantly, Cε-Nω bond could be homolytic cleaved spontaneously during the Cε-O2 bond formation in the first reaction step. This appearance mainly attributes to the Cε-Nω single bond of the L-DHMAd, which could be more feasible to cleave to maintain the Cε sp2 hybridization within the superoxo addition. The subsequent reaction step is the O1-O2 bond heterolytic cleavage, which involves a minimum energy crossing point to form the stable intermediate with Fe(IV) = O1 species at quintet state. Finally, NMe and Nω of L-DHMAd are very energetic favorable to coupling to form the N-nitroso product. This is consist with the experimental observations that two nitrogen atoms of the N-nitroso product are both from the same arginine substrate. Our work could contribute to the deeper understanding of the N-nitrosation reaction catalyzed by SznF enzyme, and might enlighten further studies of biomimetic chemistry of SznF enzyme.

Exploration of Photocatalytic Overall Water Splitting Mechanisms in the Z-Scheme SnS2/β-As Heterostructure

The Z-scheme heterostructure photocatalysts have irreplaceable advantages over other heterostructures due to their ability to separate the spatial carriers and retain strong redox ability. In this study, we explored the SnS2/β-As (β-arsenene) van der Waals heterostructure with Z-scheme properties and suitable band edge positions as a potential photocatalyst for overall water splitting. Under appropriate conditions, the hydrogen evolution reaction (HER) barrier is much closer to 0. Based on the oxidation product criteria, the SnS2/β-As heterostructure photocatalyst may generate multiple end products, including •OH, H2O2, and O2. Moreover, we screen the optimal and most possible reaction pathway OER-III under irradiation among three underlying oxygen evolution reaction (OER) mechanisms, in which the intermediate species HOOH* acts as a bridge for subsequent reactions. The solar-to-hydrogen conversion efficiency of the heterostructure can reach 17.18%. This work provides new insights into designing superior photocatalysts for overall water splitting and recognizing the OER mechanism.

Theoretical study of the influence of H-SAPO-34 modified with Zn2+ on the formation of butadiene

In the process of methanol to olefin (MTO), dienes are the precursors of aromatic species. Experimental study showed that Zn2+ modified H-SAPO-34 (Zn@H-SAPO-34) promoted aromatics formation at the initial stage of MTO reaction. Our recent work reported the reaction mechanism of the aromatization of dienes to low methylbenzene aromatics catalyzed by Zn@H-SAPO-34. Herein, using density functional theory (DFT), the possible reaction pathways of diene formation on H-SAPO-34 with and without Zn doping were systematically investigated with propene as the initial olefin. After Zn2+ modification, the acidic strength of adjacent Brønsted acid sites (BAS) is enhanced, which is conductive to the alkene-mediated butadiene formation pathway catalyzed by B-acid, and the Lewis acid produced by Zn2+ provides catalytic site for the transfer dehydrogenation reaction of methanol with propene, which promotes the formation of formaldehyde and induces the formaldehyde-mediated mechanistic pathway. Further microkinetic calculation reveals that formaldehyde-mediated pathway is the optimal reaction pathway for butadiene formation. This study demonstrates that the synergistic effect of BAS and LAS improves the formation activity of diene on Zn@H-SAPO-34. This work will help to deepen the understanding of the role of Zn2+ in the early stage of MTO reaction.

Single transition metal atoms anchored on a two-dimensional polyimide covalent-organic framework as single-atom catalysts for photocatalytic CO2 reduction: A first-principles study

We systematically investigated single transition metal atoms anchored on a two-dimensional polyimide (M@2DPI) monolayer as single-atom catalysts (SACs) for photocatalytic CO2 reduction reaction (CO2RR) with first-principles calculations. The stability of M@2DPI systems is investigated first, followed by the hybrid HSE06 functional calculations on electronic structures to determine their thermodynamic feasibility for photocatalytic CO2RR. Then the optimal reaction pathways of CO2RR are identified and the highest activity is found for M@2DPI (M = Sc, Zr and La). The electronic origin of the catalytic activity is further analyzed. Finally, we found that the candidate systems except Mn-based system are able to suppress the hydrogen evolution reaction.

The decisive role of electrostatic interactions in transport mode and phase segregation of lithium ions in LiFePO4.

Understanding the mechanism of slow lithium ion (Li+) transport kinetics in LiFePO4 is not only practically important for high power density batteries but also fundamentally significant as a prototypical ion-coupled electron transfer process. Substantial evidence has shown that the slow ion transport kinetics originates from the coupled transfer between electrons and ions and the phase segregation of Li+. Combining a model Hamiltonian analysis and DFT calculations, we reveal that electrostatic interactions play a decisive role in coupled charge transfer and Li+ segregation. The obtained potential energy surfaces prove that ion-electron coupled transfer is the optimal reaction pathway due to electrostatic attractions between Li+ and e- (Fe2+), while prohibitively large energy barriers are required for separate electron tunneling or ion hopping to overcome the electrostatic energy between the Li+-e- (Fe2+) pair. The model reveals that Li+-Li+ repulsive interaction in the [010] transport channels together with Li+-e- (Fe2+)-Li+ attractive interaction along the [100] direction cause the phase segregation of Li+. It explains why the thermodynamically stable phase interface between Li-rich and Li-poor phases in LiFePO4 is perpendicular to [010] channels.

Computational insight into electro-catalytic reduction of carbon monoxide by two-dimensional metal-embedded poly-phthalocyanine

The electrochemical conversion of carbon monoxide (CO) to value-added chemical products is promising for carbon utilization and CO removal. Herein we explored the potential of two-dimensional metal-embedded polyphthalocyanines (MPPcs) for electro-catalytic CO reduction reaction (CORR) by computational approach. The CrPPc, MnPPc, CoPPc, and MoPPc are initially screened out as the candidates. Then the optimal reaction pathways and corresponding potential determining steps (PDS) are determined by calculating free energies of all the possible intermediates. Based on our results, the CrPPc, MnPPc, and MoPPc could efficiently reduce CO into methane (CH4), among which the CrPPc exhibits the highest performance.